Variables & Values
• Have you done any experiments to
investigated variables?
• What were the variables?
• What were the values you used?
Input & Outcome
• In an experiment what is an:• input variable
• outcome variable
•
•
•
•
What happens when there are:two input variables
and
one outcome
Yeast
What is Yeast?
• Is Yeast Alive?
• How do we know?
• What do living things do?
• What do living things need?
What does Yeast need to Grow?
• What is the food for Yeast?
• What else would yeast need?
• Warmth?
• How do we know if the yeast is
growing/alive?
Activity 1
• Planning an experiment to investigate the
activity of yeast.
• Discuss & Decide
• How can you do a fair test for the effect of
sugar, the effect of warmth, and the effect
of both together on the activity of yeast?
Activity 1
•
•
•
•
What are the input variables?
What are the values?
What is the outcome variable?
What is/are the values
Think about the different
combinations.
• How many test tubes will you need?
• What outcome would you look for?
Lesson 16
Copy the results chart onto the first inside page of your book.
Each person willset up one of the tes-tubes.
In your group decide which test-tube you are going to do and write your name in the
box.
Room Temp.
No Sugar
Sugar
Warm Water
• Place balloon over the test-tube.
• Leave the experiment for 25 minutes.
• Go on to activity 3.
Activity 3
Zinc and Copper with Acid
• Put one piece of copper metal into a test
tube, another piece of zinc metal into
another test tube. Into a third test tube add
both a piece of zinc and a piece of copper.
• Add about 1cm3 of de-ionized water to
each tube. Observe what happens.
Activity 3
Zinc and Copper with acid
• Add another 1cm 3 of dilute hydrochloric
acid to each tube.
• Observe what happens.
Activity 3
Zinc and Copper with acid
• What are the input variables ?
• What is the outcome variable?
Activity 3
Zinc and Copper with acid
Copper
Water
Acid
Zinc
Copper &
Zinc
Activity 3
Zinc and Copper with acid
• Write a group sentence about the reaction
of copper and zinc reacting with dilute
hydrochloric acid, using the word interact.
Activity 2 Yeast Results
• Measure the amount of froth in each of the
yeast experiments or look how much the
baloon has blown up.
• Record your results and answer questions
1, 2 & 3.
Activity 2
Yeast Results
Not warm
(room temp.)
No Sugar
Sugar
What has happened in this experiment?
Did you expect these results?
Warm (35o)
Activity 2
Yeast Results
Not warm
(room temp.)
Warm (35o)
No Sugar
Sugar
Q 4. Write a sentence about yeast, sugar, warmth, using the word
interact.
• What other examples where two things
work together to cause something to
happen.
Thinking back
• What was difficult about this lesson?
• How did you solve the problems you had?
Homework for next lesson.
• Finish page 1 & 2.
• Can you think of some other situations
were two things interact.
Balloon Experiment
“Inflating” balloon
• Put 5 cm3 water into the test-tube.
• Put one spatula measure of instant yeast
into the test-tube.
• Put one spatula measure of sugar into two
of the test-tubes.
Place balloon over the test-tube.
Lesson 16
1. Add 5cm3 of yeast mixture to four test tubes.
2. Add 2cm3 sugar solution to two of the test tubes.
2. Stick labels on the test-tubes.(Name, Temperature & Sugar)
4. Put two of the test-tubes into the water bath and leave two in the test-tube rack.
• Repeat the procedure with two more but
do not add the sugar.
• Put one in the warm water and leave the
other in the test tube rack.
• Leave the experiment for 25 minutes.